The best definitions I can find for wide angle lens are:
"A lens of short focal length, specifically designed to provide a wider angle of view than seen by both human vision and a standard lens"
"A lens of a short focal length which makes subjects seem far away, allowing more of a subject or a scene to be fitted into a photo at close distance"
Simply put it is a type of lens with the intended purpose of capturing more view.
Any lens is merely a tool that is used at a specific time and for a specific photographic purpose.
There are many other lens types, such as fish eye, standard and telephoto lenses which are useful for long distance photography - basically like taking a photograph through a telescope.
